In a healthcare setting, Publish and Subscribe is a common pattern. For example, an everyday workflow in a laboratory setting is for a physician to create a lab order for a patient, and then receive a finalized lab report once the sample has been collected from the patient and processed.
Medplum implements a custom operation, $resend, that can be used to trigger all Subscriptions listening to a a particular resource.
Use the following FHIR extensions to customize the Subscription behavior. The behavior is non-standard, and will not necessarily work in other FHIR systems.
Subscriptions are event-driven notifications, like webhooks, are are commonly used for integrations and automations. Medplum supports subscribing to changes on FHIR resources. There is a description FHIR Subscriptions on HL7.org that describes the functionality in detail.